People have been making up such expressions for centuries to avoid cursing. There are lots of them, and I grew up hearing a steady stream of them in the southern US. Some common examples: "gosh darn" "gosh darnit" "gawd dang" "gawd dangit" "dadgum" "dadgumit"

I agree with the terms everyone else said but I do want to say colloquially, g@dd@mn isn't a bad word at all like if something is cool or surprising people say that. Even in public settings around kids or whoever :> there ya go lol

Darn it! Shoot! Crap!

This website is far stricter than necessary regarding which words are allowed. They disallow words that even children say. It's not a useful gauge of the offensiveness of a word. I have found that ChatGPT is useful for such questions as to the relative strength of a profanity in terms of how offensive it is. Also, ChatGPT is not a person, so it's not offended. If you are unfamiliar with ChatGPT, just google it. It's free for all to use.

"hot damn" is not serious enough for the situation described